| 1. | \(\left(1+\dfrac{f}{3}\right) \) | 2. | \(\left(1+\dfrac{2}{f}\right)\) |
| 3. | \(\left(1+\dfrac{f}{2}\right) \) | 4. | \(\left(1+\dfrac{1}{f}\right)\) |
| 1. | \( 1 \over 3\) | 2. | \(3 \over 1\) |
| 3. | \( 1 \over 16\) | 4. | \( 16 \over 1\) |

| (A) | the motion of the gas molecules freezes at \(0^\circ\text C.\) |
| (B) | the mean free path of gas molecules decreases if the density of molecules is increased. |
| (C) | the mean free path of gas molecules increases if the temperature is increased keeping the pressure constant. |
| (D) | average kinetic energy per molecule per degree of freedom is \(\dfrac32k_B T\) (for monoatomic gases). |
| 1. | (A) and (C) only |
| 2. | (B) and (C) only |
| 3. | (A) and (B) only |
| 4. | (C) and (D) only |